Abstract: This application provides a channel state information (CSI) feedback method, a terminal device, and an access network device. The method includes: The terminal device sends first CSI to the access network device, where the first CSI includes indication information of a first basis of statistical eigen subspace, and a period for sending the first CSI is a first period. The terminal device sends second CSI to the access network device, where the second CSI includes indication information of a first linear combination coefficient, and a period for sending the second CSI is a second period. The terminal device updates a second basis to the first basis based on trigger information. The terminal device sends third CSI to the access network device, where the third CSI includes indication information of a second linear combination coefficient, and the third CSI is generated based on the updated second basis.

Abstract: Embodiments of this application provide a channel state information (CSI) reporting method and a communications apparatus. In the method, a receiving device obtains first CSI and second CSI, and determines reference information based on the first CSI and the second CSI. The first CSI is correlated with the second CSI, the reference information includes first quantization information including projection quantization information of a common subspace and second quantization information including projection quantization information of a first non-common subspace, the common subspace includes an intersection of a first space used to quantize the first CSI and a second space used to quantize the second CSI, and the first non-common subspace includes a subspace other than the common subspace in the first space. The receiving device sends the reference information to a sending device, and the sending device determines the first CSI based on the reference information and the second CSI.

Abstract: Example precoding vector indication methods, precoding vector determining methods, and communications apparatus to reduce feedback overheads are described. One example method includes generating and sending a channel state information (CSI) report by a terminal device. A network device determines a precoding vector of one or more frequency domain units based on the CSI report. The CSI report is used to indicate M space-frequency units and a weighting coefficient of a part or all of the M space-frequency units, each of the M space-frequency units corresponds to one beam vector and one frequency domain vector, and a weighted sum of the part or all of the M space-frequency units is used to determine the precoding vector of the one or more frequency domain units.

Abstract: A reference signal indication method and an apparatus are disclosed. The method includes: a terminal device receives a plurality of pieces of first information from a plurality of network devices, where each of the plurality of pieces of first information indicates that at least one reference signal of the corresponding network device is for estimating a joint equivalent channel; receives a plurality of pieces of second information from the plurality of network devices, where each of the plurality of pieces of the second information indicates a port of the at least one reference signal; receives a plurality of pieces of coherent joint transmission data from the plurality of network devices, where one of the plurality of pieces of coherent joint transmission data includes at least one data stream and the at least one corresponding reference signal; and determines at least one joint equivalent channel based on the at least one reference signal of the plurality of network devices.

Abstract: This application provides a parameter configuration method and a communications apparatus. The method includes: receiving, by a terminal device, an indication of a first mapping relationship from a network device, where the first mapping relationship is a mapping relationship in a preconfigured first mapping relationship group, and the first mapping relationship group includes at least one mapping relationship, to indicate at least one correspondence between a reporting quantity of spatial domain vectors and a reporting quantity of frequency domain vectors; and determining, by the terminal device, the reporting quantity of spatial domain vectors and the reporting quantity of frequency domain vectors based on the first mapping relationship.

Abstract: The present disclosure relates to communication methods and communications apparatus. One example method includes determining a plurality of frequency domain units on which reporting of a precoding matrix indicator (PMI) is based in reporting bandwidth. The plurality of frequency domain units include one or more first frequency domain units and third frequency domain units obtained by dividing one or more second frequency domain units. A granularity of the first frequency domain unit is less than a preconfigured first granularity, a granularity of the second frequency domain unit is a first granularity, and a granularity of the third frequency domain unit is a predetermined second granularity. The first granularity is a granularity preconfigured for reporting a channel quality indicator (CQI), a second granularity is a granularity predetermined for reporting the PMI, and the second granularity is less than the first granularity.

Abstract: This application relates to channel state information (CSI) feedback methods and devices. One method comprises: receiving, by a terminal device from a network device, indication information of a channel state information (CSI) reporting band; determining, by the terminal device, based on the indication information, a subset of subbands in a bandwidth part configured for the terminal device for CSI reporting; determining, by the terminal device, CSI reporting priorities of the subset of the subbands based on index numbers of the subset of the subbands, wherein the index numbers of the subset of the subbands are numbered in an ascending numerical order; and sending, by the terminal device to the network device, CSI of M subbands with higher CSI reporting priorities in the subset of the subbands compared to a remainder of subbands in the subset of subbands.

Abstract: A demodulation reference signal (DMRS) sending method and an apparatus, and relates to the communication field. The method includes: a terminal device receives indication information, where the indication information indicates an expansion manner of DMRS ports in at least one of a plurality of code division multiplexing (CDM) groups corresponding to one DMRS configuration type; and sends DMRSs via DMRS ports obtained through expansion in the at least one CDM group, where the DMRS ports in the at least one CDM group include legacy DMRS ports and expanded DMRS ports.

Abstract: A terminal device obtains M pieces of first downlink channel sub-data, where each piece of first downlink channel sub-data corresponds to one data space in M data spaces. For an ith piece of first downlink channel sub-data in the M pieces of first downlink channel sub-data, the terminal device determines, based on a first dictionary corresponding to an ith data space, first information corresponding to the ith piece of first downlink channel sub-data, where M pieces of first information are determined in total. The terminal device sends first indication information, to indicate the M pieces of first information. Different data spaces can represent different channel environment information. The terminal device feeds back first information corresponding to different data spaces, so that an access network device can determine a correspondence between first information and environment information. Accuracy of the first information fed back by the terminal device is improved.

Abstract: A channel state information feedback method includes: a terminal receives first indication information from a network device, and the terminal sends channel state information to the network device. The first indication information is used to indicate a type of a right multiplication matrix in a first codebook, and the first codebook satisfies a formula (I). W is the first codebook, W1 is a port selection matrix, (II) is a linear superposition coefficient matrix, Wf is the right multiplication matrix, and (III) is a conjugate transpose of Wf, and is used by the terminal to determine the channel state information based on the first codebook. According to the method, when there are a plurality of codebooks, the codebook used by the terminal to obtain the CSI can be clearly indicated.

Abstract: This application describes a channel information feedback method and a communication apparatus. The method includes a terminal device that receives configuration information sent by a network device, where the configuration information is used to configure a feedback mode of channel information. The terminal device may feed back current channel information to the network device when the feedback mode configured by using the configuration information is a first mode. The terminal device may alternatively feeds back predicted channel information to the network device when the feedback mode configured by using the configuration information is a second mode. System performance is therefore improved by the method described in this application because channel information feedback requirements in different scenarios can be met.

Abstract: This disclosure provides methods and apparatuses for precoding in wireless communications. In an implementation, a method includes: receiving, from a terminal device, first indication information, wherein the first indication information indicates L1 space domain vectors in a space domain vector set, K1 frequency domain vectors in a frequency domain vector set, and T1 space-frequency component matrices, wherein a precoding vector of one or more frequency domain units is determined by a weighted sum of the T1 space-frequency component matrices, wherein the L1 space domain vectors and the K1 frequency domain vectors correspond to M1 space-frequency component matrices that comprise the T1 space-frequency component matrices, and determining the precoding vector of the one or more frequency domain units based on the first indication information.

Abstract: A terminal device obtains M channel estimation results. The terminal device jointly compresses the M channel estimation results by using a first encoder network, to obtain N pieces of compressed information and first state information, where the first state information represents downlink channel information, the downlink channel information includes information about downlink channels corresponding to the M channel estimation results, and the first state information is used to determine next input information of the first encoder network. The terminal device sends the N pieces of compressed information to an access network device. Downlink channels are correlated in time domain. When compressed information is obtained, in addition to a current downlink channel, a historical downlink channel is also referenced.

Abstract: This application provides a method for reporting a terminal device capability and a communications apparatus. The method includes: The terminal device generates first indication information and sends the first indication information to a network device. The first indication information is used to indicate one or more frequency domain parameters and one or more of the following capability parameters associated with each frequency domain parameter: a port quantity, a spatial domain parameter, a reference signal resource quantity, and a total port quantity. The frequency domain parameter is used to indicate a maximum quantity of frequency domain units that can be supported by the terminal device. The frequency domain unit is a frequency domain unit based on which the terminal device feeds back a PMI. Each capability parameter group may be used to indicate one combination of a plurality of parameters that can be supported by the terminal device.

Abstract: A channel measurement method and a communications apparatus. The method includes: a terminal device receives precoded reference signals from a network device, where the precoded reference signals are obtained by precoding reference signals based on K angle vectors; and generates and sends first indication information, where the first indication information is used to indicate P weighting coefficients corresponding to P angle-delay pairs, the P weighting coefficients are determined based on the precoded reference signals, each of the P angle-delay pairs includes one angle vector and one delay vector corresponding to the angle vector, a delay vector corresponding to each angle vector is preconfigured, each angle vector and the delay vector corresponding to each angle vector are obtained through uplink channel measurement, and the P angle-delay pairs and the P weighting coefficients corresponding to the P angle-delay pairs are used to determine a precoding matrix.

Abstract: This application provides a channel state information (CSI) transmission method, a communication apparatus, and a communication device. The method includes: obtaining CSI corresponding to N port groups, where the CSI includes first CSI corresponding to each of the N port groups, and N is an integer greater than 1; and sending first information and second information, where the first information includes first indication information, the first indication information indicates that the second information includes first CSI corresponding to each of K port groups, the N port groups include the K port groups, and K is a positive integer less than N.

Abstract: This disclosure provides an information transmission method and an apparatus. A first device receives N pieces of first node information from a second device, so that a first artificial intelligence model can be determined based on the N pieces of first node information and first link information, in other words, a structure of the first artificial intelligence model can be reconstructed. According to the method, when the second device indicates an artificial intelligence model to the first device, node information of a node and a connection relationship between nodes may be separately indicated. In addition, if the connection relationship between the nodes in the artificial intelligence model is a serial structure, the first link information may not be indicated, and only the node information is indicated, so that representation and transmission overheads of the artificial intelligence model can be reduced.

Abstract: This application provides a channel state information feedback method and a communication apparatus. The method includes: A first apparatus generates indication information, and sends the indication information. The indication information is used to determine at least two precoding submatrices. Different precoding submatrices correspond to different port groups, and the different port groups may correspond to different stations. According to the channel state information feedback method provided in this application, the first apparatus may indicate the information for determining the at least two precoding submatrices, so that coherent joint transmission can be performed between a plurality of stations.

Abstract: This application provides example channel measurement methods and example communication apparatuses. One example method includes determining L weighting coefficients for determining channels of K moments based on channels of M moments, where L, M, and K are all positive integers. Information about the L weighting coefficients can then be sent.

Abstract: This application provides a precoding matrix indicating and determining method and a communications apparatus. The method includes: generating, by a terminal device, first indication information, and sending the first indication information to a network device, where the first indication information indicates a spatial domain vector, a frequency domain vector, and a weighting coefficient that are used to construct a precoding matrix. When a value of a rank Z is greater than 2, Z transport layers include at least one first-type transport layer, and a maximum quantity M1 of frequency domain vectors reported for the first-type transport layer satisfies: M 1 = ? p 1 × N 3 R ? , wherein p1 is a preconfigured coefficient for determining the maximum quantity of frequency domain vectors reported for the first-type transport layer, 1?p1>0, R is a preconfigured value, N3 is a length of a frequency domain vector, Z>2, and R, N3, and Z are all positive integers.